Cell srfaces play a central role in determining the biological behavior of malignant tumors. Lectin interactions have proved useful for probing differences in membrane-surface structure between normal and malignant fibroblastic cells, examining the control of membrane surface components by cytoplasmic structures, and determining relationships of membrane-surface architecture to cell growth. However, little information is currently available on comparative surface structures of normal and neoplastic epithelial cells. The proposed research will define the phenotype of normal and neoplastic acinar cells isolated respectively from rat pancreas and a transplantable rat pancreatic acinar cell carcinoma established in our laboratory. Phenotypes of the normal and neoplastic cells will be compared by examination of cell shape, cell surface morphology, organization of the microfilamentous-microtubular cytoskeleton, lectin agglutinability, lectin receptor density and topography, receptor endocytosis, and cyclic nucleotide content. Having established the normal and neoplastic phenotype, reversion of the neoplastic phenotype to normal will be attempted with a variety of drugs and hormones active toward cyclic nucleotide levels and/or cytoskeleton organization. Finally, effects on in vitro growth of acinar carcinoma cells of drugs and/or hormones which revert neoplastic cells to a normal phenotype will be studied. The proposed studies should further our knowledge of cell surface characteristics of neoplastic epithelial cells, and provide information regarding relationship(s) between cell surfaces and the growth of pancreatic carcinoma.